How large should my circulating fan be and where should it be pointed?

I have a a 14 inch fan I have about 4 ft from my plants and its always oscillating on low and it makes my stems like tree branches. I also purchased a rapidtest digital moisture meter it's way more accurate than finger in veg I let it hit 2.8-3.5 but in flowering I do t let them get as dry as they'll wilt fast so I water when they are 3.5-4.5 on the meter and if you get one test multiple spots in pot. Herb likes dry feet like citrus trees if you keep them too wet you will have a lot of problems. IMO

Great advice....TY. Will be upping my fan size, (only 6 in) and get a moisture meter. Seems that overwatering is the most common mistake. Only growing two for now until I have everything in place. Will be cloning from these plants, Blueberry and Head Cheese, and sure to be asking more questions.
Will show more pics in a couple weeks.

Your girls look nice.
i would get in the habit of picking the plant up to feel its weight. Another indicator is the top of the soil will start to look dried out, it needs water or is getting close to being dry. Let her dry out a little bit. Before her next watering.
i also noticed you have a 600CFM intake fan, and a 240CMF exhaust fan. I would switch them. The bigger fan on your light, I take it that your exhaust is pulling the air out of your grow room. You'll have a little cooler temps. And your tent should be negative pressure, venting the smell from the grow room outside.

I use an oscilatting tower fan on its lowest speed and it has worked great for a room about the same size. My girls are well into flower and strong enough to stand on their own with no problems. I like the tower because it hits more the plant vertically and seems to be less abusive. I am using Cfl if that makes any difference.

Your fan should be small and it should not blow hard on your plants. It is to just create air movement.